Graft modified polyolefins are well known and widely used to render the generally incompatible polyolefins compatible with a variety of thermoplastics in blend compositions. The graft modifier may, for example, provide a point on the polyolefin chain where physical compatibility or miscibility between the polyolefin and thermoplastic is enhanced. Alternatively, the graft modifier may provide a site on the polyolefin chain where the polyolefin and thermoplastic undergo and are joined by chemical bonding.
Canadian Pat. No. 636,450 discloses blends of high density polyethylene with a thermoplastic resin. Although special compounding procedures are taught, the blend remains generally unsatisfactory due to the incompatibility of the polyethylene with the thermoplastic.
U.S. Pat. No. 3,250,823 discloses blends of polyethylene/maleate diester graft copolymer with polycarbonate, polycarbonamides, and polyoxymethylenes. These blends demonstrate improved compatibility between the polymer constituents.
U.S. Pat. No. 4,147,740 discloses a maleic anhydride graft modified polyethylene mixed with polyamide. The polyethylene and polyamide are chemically linked by the reaction of a terminal amine with the maleic anhydride graft moiety.
Other references reveal graft modified polyolefin in blends with thermoplastics, i.e., U.S. Pat. No. 4,071,494, Gaylord; U.S. Pat. No. 4,172,859, Epstein; and U.S. Pat. No. 4,410,661, Epstein, et al.
Thus, graft modified polyolefins are widely known and used, especially, to produce compatible blends with polyamides. However, there is a need for graft modifiers to compatibilize polyolefins with a wide range of thermoplastic materials.
Therefore, it is an object of the present invention to produce hydroxyl group graft modified polyolefins.
It is yet another object of the present invention to produce network thermoplastic blends of polyolefin and polycarbonate, polyester, poly(ester-carbonate), and/or mixtures thereof having improved impact strength, improved solvent resistance, and reduced problems with incompatibility.